1. Field of the Invention
The present invention relates to a method of reducing photoelectric device leakage current caused by residual metal ions in conjugated polymer. The present invention also relates to a conjugated polymer composition.
2. Description of the Related Art
Conjugated polymer material is used widely in organic photoelectric devices, such as polymeric light emitting diodes, organic solar cells, organic transistors and the like. The purity of the conjugated polymer material is critical to the photoelectric properties of the devices. However, there are many contamination sources, including the catalysts, reactants, and containers used in the synthesis of conjugated polymers and the environment. Purification of conjugated polymer is difficult, therefore, after purification, residual metal ions may remain. When an electric field is applied to a device comprising conjugated polymer, leakage current occurs due to the residual metal ions, reducing device efficiency. A further reaction or oxidation of conjugated polymer material is possible due to residual metal ions, thus material stability is lowered and may lead to device failure. Therefore, a method of solving the problem of photoelectric device leakage current caused by residual metal ions in conjugated polymer is called for.
U.S. Pat. No. 6,255,450 discloses a method to deaggregate electrically conducting polymer precursor molecules by the addition of surfactants, crown ethers, metal chelates, or ionic complexing agents thereto, so that dopants added thereafter can distribute uniformly in the polymer precursors to increase the electrical conductivity. It does not disclose the problem caused by residual metal ions and the method of the resolution.